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United States Patent |
5,220,113
|
Miltz
|
June 15, 1993
|
Lettuce cultivar bud 71-3
Abstract
A lettuce cultivar of the Vanguard-group is disclosed which has heads
having a mean diameter of 14 cm with medium green, glossy leaves, which is
highly resistant to corky root rot and which is adapted to summer planting
in mineral soils in summer cool regions along the Pacific Coast of North
America.
Inventors:
|
Miltz; David S. (Salinas, CA)
|
Assignee:
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Bud Antle, Inc. (Salinas, CA)
|
Appl. No.:
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381491 |
Filed:
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July 18, 1989 |
Current U.S. Class: |
800/305 |
Intern'l Class: |
A01H 005/00; A01H 005/10 |
Field of Search: |
800/1,200,230,255,DIG. 13
47/58,DIG. 1
|
References Cited
Other References
Guzman (1984) Circulars-Agr. Exp. Stat. Inst. of Food & Agr. Sci. U. of
Florida (310) pp. 1-8.
Guzman (1982) Proc. Florida State Hort. Soc. (94) pp. 182-185.
Ryder (1986) in Breeding Vegetable Crops, Ed. by Bassett, Avi Publishing
Co., Westport Conn., pp. 458-462.
|
Primary Examiner: Benzion; Gary
Attorney, Agent or Firm: Cranfill; Raymond
Claims
I claim:
1. A lettuce cultivar designated BUD 71-3 as deposited with American Type
Culture Collection under accession number 40618.
2. Propagation material of the plant of claim 1.
3. Pollen of the plant of claim 1.
4. Seeds of the plant of claim 1.
Description
FIELD OF THE INVENTION
The present invention relates to cultivars of lettuce generally, and more
particularly to cultivars of Vanguard-type lettuce.
BACKGROUND OF THE INVENTION
Lettuce, Lactuca sativa L., is a commercially important fresh leaf crop
belonging to the aster family (Asteraceae) which includes such other
important crops as sunflowers and artichokes. Lettuce is widely grown
throughout the temperate and subtropical regions of the world, and is used
predominantly as a fresh green in the human diet.
Lettuce originated from the ancestral wild species L. sativa. Today there
are over one hundred cultivars which are divided in commerce into four
large groups based on gross morphological characteristics of the gross
leaf morphology and leaf arrangement: the Romaine (or Cos) Group, the
Iceberg (or Crisp Head) Group, the Butterhead Group and the Loose Leaf
Group. These basic lettuce types frequently form the basis for grouping
lettuces as is commonly seen in supermarkets, grocery and produce stores.
Each of these basic groups is comprised of numerous cultivars, each
characterized by its own particular morphology, disease resistance, and
cultural adaptations.
The present invention is directed to a novel cultivar within the Iceberg or
Crisp Head lettuce group, by far the most popular group of lettuces sold.
Iceberg Group lettuces are characterized basically by their relatively
large, firm well formed heads. The leaves are spirally arranged on a stem
with greatly foreshortened internodes, are tightly clasping upon one
another and have a large water content, hence the name "Crisp Head".
Within the Iceberg Groups there are several clusters or assemblages of
related cultivars. One of these clusters is the Vanguard-type, named after
the Vanguard cultivar which has served as one parent of the other
Vanguard-type cultivars. Vanguard-type lettuce cultivars share the common
characteristics of being adapted to the soils and climates of the desert
growing region of western North America and possess in common certain
morphological characteristics including:
1. Dark, dull-green outer leaves;
2. Coloration of leaves extending well down the leaf base towards the core;
3. Margins of the leaves being scalloped or undulate;
4. A softer leaf texture as compared to cultivars in the Great Lakes group;
5. Heads with creamy colored interiors.
Problems with existing cultivars adapted to western conditions include a
general lack of significant resistance to corky root rot. This disease is
caused by a pathogenic soil bacterium of the genus Rhizomonas and accounts
for significant lettuce crop loss in the western United States,
particularly in the Salinas and Santa Maria valleys. The bacterium attacks
and destroys much of the root system, greatly reducing the ability of the
lettuce plant to take up water and nutrients. Loss of the root system
results in uneven stunted plants that are chlorotic and too small to
harvest.
Unlike other leaf crops which are cooked and thus may be canned or
otherwise processed, lettuce is almost universally sold as a fresh
vegetable. Thus, its market ready appearance and perishability are key
factors governing salability. Existing cultivars are often inferior
because they produce heads which are undesirably small or which have loose
or otherwise misshapen leaves. Leaf color of both external and internal
head leaves is important for the reason that consumers desire richly
colored greens for their salads and will pass over lettuce heads which are
pale, clear or milky colored.
Existing Vanguard-type cultivars fail to exhibit all of the desired
characteristics necessary for optimal production during the summer growing
season. Vanguard is noted for its excellent coloring, particularly on
leaves inside the head, its flat ribs and high quality, but is susceptible
to a host of diseases including corky root rot, downy mildew, and tipburn,
and is adapted for early spring harvest in the climate and soils of
California's Imperial Valley and adjacent desert regions. Sea Green is
most notable for its rich green color and its moderate resistance to big
vein, but it is susceptible to corky root rot and tipburn, and is
harvestable only in the spring. Salinas has been a popular cultivar
adapted to the soils and climate of coastal California and is
characterized by a resistance to bolting and tip burn, and by a dull green
outer leaves with cream-colored interior leaves, and a relatively small
head size of less than 13.5 cm. Salinas is not resistant to corky root
rot. Montello is somewhat resistant to corky root rot, but is adapted to
muck soils in the midwest and northeastern United States. It cannot be
grown commercially in the coastal valleys of California.
Although Salinas and cultivars derived from it are adapted to the climates
and soils of coastal California, there exists a need for an improved
coastal cultivar of Iceberg-Group lettuce that has heads which are large
in size and have a rich green color; which have more uniformly shaped,
tightly clasping leaves which are adapted to summer growth and harvest;
and which are resistant to corky root rot.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a lettuce cultivar that
is adapted to the cool summer climate and soils prevalent along the west
coast of the United States, particularly the coastal valleys of
California.
It is another object of the present invention to provide a lettuce cultivar
that is resistant to corky root rot.
It is yet another object of the present invention to provide a cultivar of
lettuce that is comparable to Salinas in resistance to bolting during warm
weather and long days.
It is a further object of the present invention to provide a lettuce
cultivar which is large headed and firm, and has rich green leaves which
are broad, regularly shaped and firmly overlapping.
The present invention meets these objectives by providing a novel
Vanguard-type lettuce cultivar which is adapted for harvest in the cool
summer climate along the United States west coast, which is resistant to
corky root rot, and which is characterized by having large, firm heads
with well formed, rich green, tightly overlapping leaves.
BRIEF DESCRIPTION OF THE FIGURES
FIG. 1 is a genealogy of the lettuce cultivar of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
Definitions
The following definitions will be helpful in the discussion of the BUD 71-3
cultivar that follows.
Cotyledon. In the case of lettuce, one of a pair of leaves formed on an
embryo within a seed which upon germination are the first leaves to
emerge.
Fourth Leaf. The fourth leaf formed on the lettuce plantlet subsequent to
the emergence of the cotyledons.
Frame Leaf. The first set of freely recurring leaves which are external to
the head.
Market Stage. The developmental stage reached by a crop plant at which time
the plant is ready for harvest. In Iceberg Group cultivars of lettuce, it
is that stage at which the head has reached a maximum size before bolting
but in which most of the head leaves are still tightly clasping.
Market Trimmed. The harvested and trimmed head of lettuce which is ready to
be packed and shipped to market.
Butt. The bottom portion of the lettuce head which includes the stem and
adjacent leaf bases of the outermost head leaves.
Core. The stem of the lettuce head on which the leaves are borne.
Bolt. The process during which the stem within the lettuce head greatly
elongates, causing the head to lose its shape and resulting ultimately in
the producing of a flowering stalk.
Corky Root Rot. A disease of some lettuce cultivars caused by a pathogenic
soil bacterium classified as a member of the genus Rhizomonas.
Origin and Parentage of BUD 71-3
Referring now to FIG. 1 the genealogy of lettuce cultivar of the present
invention, herein designated as BUD 71-3, will now be described. BUD 71-3
is a Vanguard-type lettuce derived by pedigree selection after
intercrossing cultivars Montello and Salinas. Pollen from Montello plants
was used to fertilize female Salinas plants according to the mist
depollination technique outlined by Ryder and Johnson, Hortscience 9: 584
(1974), which is incorporated by reference as though fully set forth
herein. Montello is a lettuce cultivar well adapted to summer season in
north central and northeastern Wisconsin muckland soils. Montello produces
heads having a mean diameter similar to BUD 71-3 in the northeast, but
produces substantially smaller heads when grown along the west coast of
the United States. The leaves are moderately ribby and are finely dentate
along the margin. The heads are unprotected and subject to sunscald.
Montello is highly resistant to corky root rot, scoring a 1.3 on a scale
of 0 to 5 wherein 0 represents complete resistance. Montello is not well
adapted to the mineral soils of California, where it produces heads of
below normal size which sunscald easily and which suffer early senescence.
Salinas is a lettuce cultivar well adapted to the mineral soils and cool
summer of coastal western North America. Salinas produces heads having a
mean diameter similar to BUD 71-3, except when infected with corky root
rot when the head size is greatly diminished. The leaves are dull green in
color, matching most closely 146A on the Royal Horticultural Society Color
Chart, and have coarsely dentate to scalloped or wavy margins. The heads
are adequately covered at maturity and are resistant to sunscald and tip
burn. Salinas is susceptible to corky root rot, scoring a 5 on a scale of
0 to 5 where 0 represents complete resistance. Salinas is widely planted
in summer-cool coastal valleys along the United States west coast.
In September 1982, 12 seeds from each of the lettuce cultivars Montello and
Salinas were planted in greenhouse in Salinas, Calif. At flowering stage,
the cultivars were intercrossed as described above. F.sub.1 seed was
harvested from eight successfully cross-fertilized Salinas plants and was
massed in June 1983.
F.sub.1 seed was planted in November 1983 and allowed to self pollinate.
F.sub.2 seed was harvested in June 1984. The F.sub.2 seed was planted
immediately thereafter and produced young lettuce plants by September
1983. From these plants, an individual was selected for resistance to
corky root rot and for Vanguard-type leaves with smooth butt and
desireable rich green color. This individual was designated IC3-2-T2, and
allowed to go to seed.
In January 1985, F.sub.3 seed was harvested from individual IC3-2-T2. This
F.sub.3 was planted shortly thereafter in Salinas. An individual
designated IC3-2-T2-B1 was selected based upon the above described
characteristics and was transplanted and allowed to go to seed.
In January 1986, F.sub.4 seed produced by individual IC 3-2-T2-B1 was
planted. Ten plants were selected out and designated and allowed to go to
seed in July 1986. Seed from each of these plants was designated as a
separate line, 71-1 through 71-10. Seed from each of these lines was
immediately planted out in August 1986.
Line 71-3 was chosen for further development and seed increase. F.sub.5
seed was produced by single seed descent and harvested in early 1987. The
F.sub.5 seed was planted in January of 1987 in Salinas in small trial
plots. F.sub.6 seed was produced by family selection increasing the seed
from line 71-3 and was harvested in the Fall of 1987.
The F.sub.6 seed was established in late 1987 at Salinas. The line was
planted out in large trial plots and observed in the Summer of 1988.
Thereafter the seed was harvested and bulked to produce the cultivar of
the present invention, BUD 71-3.
Morphological Description of BUD 71-3
The lettuce cultivar BUD 71-3 will now be described. The terminology used
herein to describe BUD 71-3 are those used by the Plant Variety Protection
Office, unless otherwise noted, in PVPO Form LS-470-1, "Objective
Description of Variety: LETTUCE."
1. PLANT TYPE. BUD 71-3 is a Vanguard-type lettuce cultivar. These are
lettuce cultivars falling within the Iceberg or Crisp Head group of
lettuces and are adapted to western climates and soils.
2. SEED. Seed is brown in color. Light is not required for germination, as
is the case with some other lettuce cultivars. The seeds are susceptible
to thermodormancy.
3. COTYLEDON TO FOURTH LEAF STAGE. Cotyledons upon emergence are spatulate.
The fourth leaf is ovate with a length/width index (L/W.times.10) of 15,
with a coarsely dentate apical margin and a moderately dentate basal
margin. The fourth leaf is further characterized by being moderately
undulate, unrolled, slightly cupped, unreflexed, and having a medium green
color (a rich green color similar to the cultivar Sea Green) without
anthocyanic expression.
4. MATURE LEAVES. Mature leaves are broadly ovate, large, thick, moderately
glossy and blistered, medium green in color, most closely matching color
146B of the Royal Horticultural Society Color Chart, with no anthocyanic
expression (both external and outmost internal head leaves), leaf
trichomes absent; margin with moderately deep incisions, crenate and
moderately undulate as in the cultivar Vanguard.
5. PLANT AT MARKET STAGE. Frame leaves have a spread of about 41 cm. The
heads are firm, spherical, and large having a diameter of about 14 cm with
a standard deviation of 1.8 cm as measured on a market ready head having a
single cap leaf, and weighing 768 gm with a standard deviation of 194 gm.
6. BUTT (BOTTOM OF MARKET-TRIMMED HEAD). The butt is rounded with
moderately raised midribs on adjacent leaf bases.
7. CORE (STEM OF MARKET-TRIMMED HEAD). The core has a diameter of
approximately 32 mm and a height of approximately 6.2 mm, as measured from
base of head to stem apex within the head.
8. BOLTING. BUD 71-3 is a medium bolter as compared to the cultivar
Salinas, taking approximately 141 days to bolt as measured from the time
the seed first receives water sufficient for germination. The mature seed
stalk reaches 127 cm in length, with total spread of the bolted plant
reaching 42 cm. The bolter leaves (cauline leaves) are straight with
dentate margins and are dark green in color. The inflorescence is largely
terminal with some lateral shoots. Flowering basal side shoots are absent.
9. MATURITY. Plants of BUD 71-3 were planted in the northwest Salinas
Valley, Calif. on Jun. 21, 1988 and matured to market-ready stage in
approximately 70 days.
10. ADAPTATION. BUD 71-3 is adapted for summer planting along the United
States west coast in mineral soils.
DISEASE AND STRESS REACTIONS: Bud 71-3 is highly resistant to corky root
rot scoring a 1.8 on a 0 to 5 scale where 0 signifies complete resistance
and 5 signifies complete susceptibility, and is somewhat resistant to
tipburn and heat.
Propagation of BUD 71-3
Bud 71-3 may be propagated from seed or by tissue culture techniques.
Seed production is achieved by sowing existing seed in flats at
68.degree.-70.degree. F. Seedlings or young plantlets are then transferred
to containers or beds and are grown at 85.degree.-95.degree. F. to induce
bolting. The heads may need to be cut open or broken to permit elongation
of the stem and inflorescence. Plants are allowed to self and the
resulting seed are then collected.
Propogation may be had using explant material to produce leaf callus which
is subsequently induced to form plantlets according to the methods
described in Alconero, R. Hortscience 18:305-307 (1983), the contents of
which are expressly incorporated herein.
Axial buds can be excised from existing plants and then can be induced to
form rooted plants using techniques well known in the art.
Production Methods of BUD 71-3
Production of market ready lettuce from BUD 71-3 proceeds as follows. Seed
is directly sown on double row beds of 40 in. centers. Rows on a bed are
about 15 in. apart with seed deposited at intervals of 2 to 3 in. along
the row.
Each seed is usually encapsulated in, or "pelleted," with inert clays to
form a large and uniform pill. Encapsulation in this way facilitates
positioning and planting of the seed which is small.
In California, the plants are watered during the germination phase using
sprinkler systems. As the plants mature, watering is accomplished by
irrigating the furrows between the rows.
Four to six weeks after germination, lettuce is thinned to produce a final
stand in which plantlets are spaced apart in the row at distances of about
10 in.
In mineral soils common in the west, fertilization with nitrogen,
phosphorus and, less frequently, potassium is required.
Harvest time varies according to the local climatic conditions. BUD 71-3
takes approximately 70 days from planting to harvest in the coastal
valleys of California.
Deposit of BUD 71-3
Seeds of BUD 71-3 have been deposited with the American Type Culture
Collection, 12301 Parklawn Dr., Rockville, Md. 20852. The deposit was made
on Jun. 14, 1989 and received accession number ATCC 40618
Although the cultivar of the forgoing invention has been described and
illustrated, it should be understood that certain changes and
modifications may be practiced within the scope of this invention without
departing from the scope of the invention as set forth in the accompanying
claims.
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